Manufacture of chromium oxid.



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ALBERT EDTVARD GESSLER, 01E CLIFTON, NEW YORK.

MANUFACTURE OF CHROMIUM 0X11).

No Drawing.

ture of Chromium Oxid, of which the fol-.

lowing is a specification.

My invention relates to the production of green oxid of chromium fromchromates without the employment of external heat and consists generallyin the-ignition of a proper mixture of a chromate, a reducing agent anda highly oxidizing agent.

The present known methods of producing green oxid of chromium fromchromatescon-' sist in introducing amixture of the chromate and areducing agent into a furnace and together and placed in a The mixtureis then' ignited by means of 'a' heating to a high temperature,generally from 500 C. to 700 0., the heat being necessarily obtainedfrom an external source. I'havefoun'd that a fuel and apparatus can. beobtained by addgreat saving in time,

ing to the mixture of chromate and reducing agent a quantity of a highlyoxidizing agent which will increase the chemical'energy of the mixtureand allow the formation of oxid of chromium by mere ignition and "selfcombustion of the mixture.

Tn following my process, the chromates I preferablyemploy are the alkalimetal bi chromates, for example sodium bichromate and potassiumbichromate, the reducing agents being preferably sulfur, carbon oraluminum, and the highly oxidizing agents.- being preferably alkalimetal chlorates, for

and peroxide. The following is an example of one method of performing myinvention. Fiftyexample sodium chlorate, potassium chlorate threehundred (5300) parts of powdered calcined sodium bichromate, onethousand (100@ parts of sulfur flour, and one hundredand-'twenty-five'(125) parts of powdered sodiumv chlorate are thoroughlymixed proper receptacle.

direct flame: and allowed .to burn through self combustlon. 'Whenthecombustion has been completed and the mixture converted. into 'a darkgreen. bulky -mass, it is allowed,

Patented Uct. ac, rain.

to cool and is thoroughly washed to remove the soluble by-products, anddried if desired. The resulting product is practically pure green oxidof chromium.

The fifty three hundred (5300) parts of powdered calcined sodiumbichromate may be substituted by fifty-nine hundred (5900) parts ofpowdered calcined potassium bichromate, the remainder of the practicallythe same.

1 do not limit myself to the proportions or particular chemicalsmentioned herein, all of which may be varied without going beyond thescope of my invention which comprises the production of green oxid ofchromium through the ignition and self combustion of a mixture of asuitable chromate, reducing agent and highly oxidizing agent.

Having described my invention, what I claim is:

1. The process of producing green oxid of chromium-which comprisesmaking a mixture of an alkali-metal chro'mate, a reducing agent capableof reducing the chromate to chromium oxid, and an oxidizing agentcaprocess being v pable of sustaining combustion, igniting the -product.r

2. The process of producing green oxidof chromium which comprises makinga mixture of an-alkali-metal bichromate, a reducing agent capable ofreducing the bichromate to chromium oxid, and an oxidizing agent capableof sustaining combustion, igniting the mixture within a receptacle,allowing the combustion to proceed-to the formation of chromium oxid,and lixiviating the resultant product. u g

3. The process of producing greenom'd of chromium which comprises makinga mixture of an alkali-metal bichromate, sulfur,

' and an oxidizing agent capable of sustaining combustion, igniting themixture within a receptacle, allowing the combustion to proceed to theformation of chromium oxid,'and

-.lixiviating the resultant product.

4. The process of producing green oxid ofchromiumwhich comprises theignitionand self combustion of a mixture of an-alkalimetal bichi'omate,sulfur and an alkali metal In testimony whereof I have signed mychlorate. I name to this specification in the presence of 5. The processof producing green oxid of two subscribing witnesses.

chromium which "comprises mlxmg sodium ALBERT EDWARD GESSLER. 5biohromate, sulfur vend. sodium chlorate, Witnesses: igniting the'mixture, allowing the comple- CHAS. PoPP,

tion of the combustion, and'lixiviating. H. SCHOEFFLER.

